Quantitative analysis on forest resource management along with environmental conservation and economic development in mountainous areas

该项目的目的是对山区森林资源管理与环境保护和经济发展进行定量分析。我们的结果是：1。成本分析：在目前木材价格水平下，可能无法进行造林和采伐。在使用补贴的情况下，重新种植仍然存在困难。因此，有必要更新和修改补贴政策，以实现我国森林资源的可持续管理。最优间伐制度：利用提出的动态规划模型，揭示补贴对间伐的管理效果。补贴越多，最佳轮转年龄往往越长，最高可达40年。将贴现率从1%更改为3%，观察到1%和2%的大影响，而3%几乎没有影响。木材需求/供应模型：宫崎作为最大的杉木生产州之一，国内木材需求的相对价格弹性为-4.6，非常有弹性。在岩手县，原木需求的相对价格弹性为-0.29。静冈县靠近主要木材消费州，在木材供应方面表现较好森林资源管理：基于目前的森林蓄积量水平，我们使用基于LP的采伐模型分析了随着时间的推移，在可持续的方式下可以预期多少木材供应。在宫崎，允许10%的收获流量逐期变化，周期（5年）的收获水平为9490000 m^3，而广岛在30%的允许下为2095000 m^3。这是因为与宫崎等主要木材生产州相比，广岛的生产基础设施并不发达，也因为大量的美国原木是进口的，这意味着国内木材生产环境没有必要改善。

The objective of the project was to conduct quantitative analysis on forest resource management along with environmental conservation and economic development in mountainous areas. Our results are :1. Cost analysis : Under the current level of timber price level, silvicultural and harvesting practices may not be carried out. With use of subsidies there still remains difficulty for replantation. As a result, it will be necessary to renew and modify the subsidy policy in order to achieve our sustainable forest resorce management.2. Optimal thinning regime : With use of the proposed dynamic programming model, management effect of subsidy on thinning was revealed. The more the subsidy, optimal rotation age tends to be longer, ending up to 40 years. Changing discount rate from 1 to 3%, large effect was observed for 1 and 2% as compared to almost no effect for 3%.3. Timber demand/supply modeling : In Miyazaki as one of the largest sugi producing states, relative price elasticity of domestic lumber demand was -4.6, very elastic. In Iwate, relative price elasticity of log demand was -0.29. Shizuoka, which is close to the major timber consuming states, showed better results on timber supply.4 Forest resource management : Based on the current forest stocking level, we analyzed how much of timber supply could be expected on the sustainable fashion over time by use of the LP based harvesting model. In Miyazaki, allowing 10% change in harvest flow period by period, periodical (5 years) harvest level became 9490,000 m^3, which that was 2095,000 m^3 for Hiroshima under 30% allowance. This is because in Hiroshima infrastructure for production is not well developed as opposed to the major timber producing states, e.g., Miyazaki, and also because a large amount of US logs is imported, implying no necessity of improvement for domestic timber producing environments.